All crypto currencies have a blockchain and a rewards system for people working and keeping the blockchain safe. There are several possible mechanisms to achieve a high level of security and stability, but all have an energetic cost that is paid by the person making this work.
To encourage people to maintain a secure network, there is a rewards system based on the work done. One of these methods is the DPOS (Delegated Proof of Stake). It is defined as one of the most efficient, fast and decentralized consensus patterns. The customizable parameters of the network, such as the fee, the block time, the block size, can be edited with the voting system of the delegates. Obviously, it is not necessary to have an entity or a central authority. It's all decentralized!
The first crypto currencies that implemented the DPOS model was Bitshares.
The DPOS is a POS (proof of stake) variant developed to reduce the energy used to keep the network secure. In the POS model, every wallet containing coins can participate in the phase of POS and by validating block and transactions, and earn coins in return. In the DPOS model, every wallet containing coins can vote for a delegate who participate in the validation phase, maintaining the blockchain safe and earning coins in exchange.
The fact that only a few chosen "Delegates" can participate in the network security, would seem to go against the decentralization paradigm. However, considering the Bitcoin world where the mining pools took control of the network, having a fixed number of delegates keeps decentralization at an even lower cost than other mechanisms.